/*******************************************************************************
 * Copyright (c) 2004, 2005 Elias Volanakis and others.
�* All rights reserved. This program and the accompanying materials
�* are made available under the terms of the Eclipse Public License v1.0
�* which accompanies this distribution, and is available at
�* http://www.eclipse.org/legal/epl-v10.html
�*
�* Contributors:
�*����Elias Volanakis - initial API and implementation
�*******************************************************************************/
package org.asem.eclipse.mii.model.parts;

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.util.List;

import org.asem.eclipse.mii.model.abs.AbstractModelElement;
import org.asem.eclipse.mii.model.abs.AbstractModelShape;
import org.asem.eclipse.mii.model.abs.ShapeConstants;
import org.asem.eclipse.mii.model.commands.ShapeCreateCommand;
import org.asem.eclipse.mii.model.commands.ShapeSetConstraintCommand;
import org.asem.eclipse.mii.model.shapes.ShapesDiagram;
import org.eclipse.draw2d.ConnectionLayer;
import org.eclipse.draw2d.Figure;
import org.eclipse.draw2d.FreeformLayer;
import org.eclipse.draw2d.FreeformLayout;
import org.eclipse.draw2d.IFigure;
import org.eclipse.draw2d.MarginBorder;
import org.eclipse.draw2d.ShortestPathConnectionRouter;
import org.eclipse.draw2d.geometry.Rectangle;
import org.eclipse.gef.EditPart;
import org.eclipse.gef.EditPolicy;
import org.eclipse.gef.LayerConstants;
import org.eclipse.gef.commands.Command;
import org.eclipse.gef.editparts.AbstractGraphicalEditPart;
import org.eclipse.gef.editpolicies.RootComponentEditPolicy;
import org.eclipse.gef.editpolicies.XYLayoutEditPolicy;
import org.eclipse.gef.requests.ChangeBoundsRequest;
import org.eclipse.gef.requests.CreateRequest;


/**
 * EditPart for the a ShapesDiagram instance.
 * <p>
 * This edit part server as the main diagram container, the white area where everything else is in. Also responsible for
 * the container's layout (the way the container rearanges is contents) and the container's capabilities (edit
 * policies).
 * </p>
 * <p>
 * This edit part must implement the PropertyChangeListener interface, so it can be notified of property changes in the
 * corresponding model element.
 * </p>
 * 
 * @author Elias Volanakis
 */
@SuppressWarnings({"rawtypes", "unused"})
class DiagramEditPart extends AbstractGraphicalEditPart implements PropertyChangeListener {

    /**
     * Upon activation, attach to the model element as a property change listener.
     */
    public void activate() {
        if (!isActive()) {
            super.activate();
            ((AbstractModelElement) getModel()).addPropertyChangeListener(this);
        }
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.eclipse.gef.editparts.AbstractEditPart#createEditPolicies()
     */
    protected void createEditPolicies() {
        // disallows the removal of this edit part from its parent
        installEditPolicy(EditPolicy.COMPONENT_ROLE, new RootComponentEditPolicy());
        // handles constraint changes (e.g. moving and/or resizing) of model
        // elements
        // and creation of new model elements
        installEditPolicy(EditPolicy.LAYOUT_ROLE, new ShapesXYLayoutEditPolicy());
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.eclipse.gef.editparts.AbstractGraphicalEditPart#createFigure()
     */
    protected IFigure createFigure() {
        Figure f = new FreeformLayer();
        f.setBorder(new MarginBorder(3));
        f.setLayoutManager(new FreeformLayout());

        // Create the static router for the connection layer
        ConnectionLayer connLayer = (ConnectionLayer) getLayer(LayerConstants.CONNECTION_LAYER);
        connLayer.setConnectionRouter(new ShortestPathConnectionRouter(f));

        return f;
    }

    /**
     * Upon deactivation, detach from the model element as a property change listener.
     */
    public void deactivate() {
        if (isActive()) {
            super.deactivate();
            ((AbstractModelElement) getModel()).removePropertyChangeListener(this);
        }
    }

    private ShapesDiagram getCastedModel() {
        return (ShapesDiagram) getModel();
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.eclipse.gef.editparts.AbstractEditPart#getModelChildren()
     */
    protected List getModelChildren() {
        return getCastedModel().getChildren(); // return a list of shapes
    }

    /*
     * (non-Javadoc)
     * 
     * @see java.beans.PropertyChangeListener#propertyChange(PropertyChangeEvent)
     */
    public void propertyChange(PropertyChangeEvent evt) {
        String prop = evt.getPropertyName();
        // these properties are fired when Shapes are added into or removed from
        // the ShapeDiagram instance and must cause a call of refreshChildren()
        // to update the diagram's contents.
        if (ShapeConstants.CHILD_ADDED_PROP.equals(prop) || ShapeConstants.CHILD_REMOVED_PROP.equals(prop)) {
            refreshChildren();
        }
    }

    /**
     * EditPolicy for the Figure used by this edit part. Children of XYLayoutEditPolicy can be used in Figures with
     * XYLayout.
     * 
     * @author Elias Volanakis
     */
    private static class ShapesXYLayoutEditPolicy extends XYLayoutEditPolicy {

        /*
         * (non-Javadoc)
         * 
         * @see ConstrainedLayoutEditPolicy#createChangeConstraintCommand( ChangeBoundsRequest, EditPart, Object)
         */
        protected Command createChangeConstraintCommand(ChangeBoundsRequest request, EditPart child, Object constraint) {
            if (child instanceof ShapeEditPart && constraint instanceof Rectangle) {
                // return a command that can move and/or resize a Shape
                return new ShapeSetConstraintCommand((AbstractModelShape) child.getModel(), request,
                        (Rectangle) constraint);
            }
            return super.createChangeConstraintCommand(request, child, constraint);
        }

        /*
         * (non-Javadoc)
         * 
         * @see ConstrainedLayoutEditPolicy#createChangeConstraintCommand(EditPart, Object)
         */
        protected Command createChangeConstraintCommand(EditPart child, Object constraint) {
            // not used in this example
            return null;
        }

        /*
         * (non-Javadoc)
         * 
         * @see LayoutEditPolicy#getCreateCommand(CreateRequest)
         */
        protected Command getCreateCommand(CreateRequest request) {
            Object childClass = request.getNewObjectType();
            return new ShapeCreateCommand((AbstractModelShape) request.getNewObject(), (ShapesDiagram) getHost()
                    .getModel(), (Rectangle) getConstraintFor(request));

        }

    }

}